Bellows seal

ABSTRACT

A mechanical seal construction comprising a pair of seal elements having mutually contacting sealing faces, one seal element being fixed with respect to a wall and the other seal element being capable of rotation in response to rotation of a shaft. A further element is nonrotatably connected to the shaft and is sealingly interconnected to said other seal element by a flexible bellows-type seal. Said further element comprises an axially split two-part collar surrounding and fixedly connected to the shaft and having a suitable packing associated therewith for sealingly engaging the shaft. The packing, in a preferred embodiment, comprises an annular ringlike sealing member constructed of multilayer graphite material compressed axially between the two-part collar. The collar has wedge means thereon for causing the sealing member to be radially compressed against the shaft to sealingly engage same.

United States Patent [191 Adams NOV. 20, 1973 21 Appl. No.: 218,392

[52] US. Cl 277/89, 277/42, 277/90 [51] Int. Cl F16j 15/34 [58] Field ofSearch 277/81, 85, 89, 123,

[56] References Cited UNITED STATES PATENTS 4/1959 Amirault et al 277/89l/l959 Parks et al. 277/203 Primary Examiner-Samuel B. RothbergAssistant Examiner-Robert I. Smith AttorneyWoodhams, Blanchard and Flynn[57] ABSTRACT A mechanical seal construction comprising a pair of sealelements having mutually contacting sealing faces, one seal elementbeing fixed with respect to a wall and the other seal element beingcapable of rotation in response to rotation of a shaft. A furtherelement is nonrotatably connected to the shaft and is sealinglyinterconnected to said other seal element by a flexible bellows-typeseal. Said further element comprises an axially split two-part collarsurrounding and fixedly connected to the shaft and having a suitablepacking associated therewith for sealingly engaging the shaft. Thepacking, in a preferred embodiment, comprises an annular ringlikesealing member constructed of multilayer graphite material compressedaxially between the two-part collar. The collar has wedge means thereonfor causing the sealing member to be radially compressed against theshaft to sealingly engage same.

8 Claims, 3 Drawing Figures BELLOWS SEAL CROSSREFERENCE TO RELATEDAPPLICATION This application is related to my copending application Ser.No. 837,061, filed July 27, 1971, and entitled MULTILAYER GRAPHITE SEALRING, now US. Pat. No. 3,655,206.

FIELD OF THE INVENTION This invention relates to a mechanical sealconstruction and, in particular, to an improved bellows-type sealconstruction utilizing a shaft packing, preferably of multilayergraphite material, for sealingly connecting one end of the bellows tothe shaft.

BACKGROUND OF THE INVENTION Bellows-type mechanical seal constructionsof various forms have been extensively utilized on pumps and relateddevices for creating a sealed relationship between a relativelyrotatable shaft and a surrounding wall or housing. However, the knownbellows-type seal constructions have possessed structural andoperational limitations which have limited their scope of usage forextremes of operating conditions.

For example, when the seal construction is to be utilized throughrelatively wide temperature ranges, such as within the range ofapproximately between 65 F.

to approximately 500 F., then the bellows is normally sealinglyconnected to the shaft by means of a clamping collar which has aconventional elastomeric (or Teflon) packing ring associated therewithfor sealingly engaging the cylindrical peripheral surface of the shaft.While these bellows seal constructions do operate satisfactorily withinthis temperature range, nevertheless the elastomeric packing rings arenot useable when the temperature exceeds 500 F. since the elastomersrapidly deteriorate when exposed to such a high temperature. Also, manyotherwise desirable elastomers have an upper temperature limit of onlyapproximately 200250 F. The elastomers also tend to harden excessivelywhen exposed to temperatures in the neighborhood of or below 65 F.,whereby they lose their resiliency and are incapable of effectivelyfunctioning as a seal or packing. Thus, the known bellows-type sealconstmctions utilizing an elastomeric packing are successfully usableonly within a limited temperature range, and are not successfully usablein situations where the temperatures exceed this range.

In order to overcome the problems associated with the use of elastomericpackings, particularly when the bellows-type seal construction is to beutilized in temperatures in excess of 500 F., the bellows-type sealconstruction has generally necessarily required that the packing be ofan entirely different type in order to operate under these hightemperature conditions. For this purpose, the bellows-type sealconstruction has generally been provided with a metal or asbestos gasketpositioned between the bellows clamping collar and the shaft forcreating a sealed relationship therebetween. However, such metal 'orasbestos gaskets can be sealingly related to the shaft only by providinga stepped shaft arrangement so that the metal or asbestos gasket isaxially clamped between the clamping collar and a shoulder formed ontheshaft. This arrangement is obviously undesirable since itsubstantially increases the cost of the overall assembly in that itrequires the provision of a stepped shaft, rather than utilizing a shafthaving a substantially uniform diameter. Further, the positioning of theseal assembly is greatly restricted since it can be positioned onlywhere such a step or shoulder exists. Still further, the necessity ofproviding a stepped shaft often substantially complicates the mountingof the bellows-type seal construction between the shaft and thesurrounding wall, and also makes maintenance and/or repair of the sealassembly, particularly at a job site, extremely difficult.

It has also been discovered that packings constructed of asbestos, whenutilized for extended periods of time at temperatures above 600 F.,become extremely hard, whereby the asbestos or asbestos combination nolonger effectively functions as a seal. i

Thus, it is an object of the present invention to provide an improvedmechanical seal construction, particularly a bellows-type sealconstruction, having an improved packing coacting between the bellowscollar and the shaft for creating a sealed relationshp therebetweenwhile also permitting the seal construction to be substantiallyuniversally utilized under substantially all environmental conditions.

A further object of the present invention is to provide an improvedbellows-type seal construction, as aforesaid, which can be utilizedunder conditions of extremely high or extremely low temperatures,particularly above 600 F. and below --l00 F., which can be utilized withall types of corrosive and abrasive fluids, and which can besuccessfully used in radioactive environments.

Still a further object of the present invention is to provide animproved bellows-type seal construction, as aforesaid, which utilizes apacking coacting between the bellows collar and the shaft for creating adesirable sealed relationship therebetween, which packing is able tocoact directly with the periphery of the shaft without requiring the useof a stepped or shouldered shaft.

Another object of the present invention is to provide an improvedbellows-type seal construction, as aforesaid, wherein the packing ringdisposed for coaction between the shaft and the bellows collar isconstructed of a multilayer or laminated graphite material, with saidgraphite shaft packing being compressed between two substantiallytransverse and parallel supporting surfaces, and wedge means coactingwith the packing ring for simultaneously radially and axiallycompressing the graphite packing into sealing engagement with theperiphery of the shaft.

Other objects and purposes of this invention will be apparent to personsacquainted with devices of this type upon reading the followingspecification and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a central sectional view ofa mechanical seal assembly constructed according to the presentinvention.

FIG. 2 is an enlarged fragmentary sectional view of a portion of FIG. 1.

FIG. 3 is an enlarged fragmentary sectional view of a portion of FIG. 2and specifically illustrating therein the improved shaft packing of thepresent invention.

Certain terminology will be used in the following description forconvenience in reference only and will not be limiting. The wordsupwardly, downwardly, leftwardly and rightwardly will designatedirections in the drawings to which reference is made. The

words inwardly and outwardly will refer to directions toward and awayfrom, respectively, the geometric center of the device and designatedparts thereof. Said terminology will include the words abovespecifically mentioned, derivatives thereof and words of similar import.

Further, the terminology multilayer as utilized herein includes not onlyan annular packing ring constructed of a plurality of individualplatelike members axially stacked together, but also a continuous flatmember wound to form either a helical or a concentric spiral. Further,the individual layers of the packing ring may be come at least partiallybonded together when a compression force is applied thereto.

SUMMARY OF THE INVENTION In general, the objects and purposes of theinvention are met by providing a mechanical seal construction for usebetween a wall and a shaft extending therethrough and rotatable relativethereto, and wherein the mechanical seal construction has a pair ofsealing members having mutually contacting sealing faces. One of thesealing members is fixed to the wall whereas the other sealing member iscapable of rotation in response to rotation of the shaft. The othersealing member is fixedly and sealingly connected to one end of anelongated flexible bellows seal surrounding the shaft, and the other endof the bellows seal is fixedly and sealingly connected to a clampingcollar. The champiing collar surrounds and is fixedly clamped to theshaft and is provided with a suitable annular packing ring associatedtherewith for sealingly engaging the shaft.

In a preferred embodiment of the invention, the collar is of a two-piececonstruction and includes two axially separable rings which are normallyfixedly held together. One of the collar rings has an annular recessformed therein directly adjacent the other collar ring and encirclingthe shaft, which annular recess has a tapered outer peripheral wall. Apacking ring, preferably of a multilayer graphite material, is disposedwithin the recess and is axially clamped and compressed between the twocollar members, whereby the tapered outer surface of the recess acts asa wedge and causes the packing ring to be radially compressed intosealing engagement with the periphery of the shaft. The shaft ispreferably provided with a substantially uniform diameter in the regionof the packing ring so that the packing ring is urged radially intosealing engagement therewith.

DETAILED DESCRIPTION FIG. 1 illustrates therein a mechanical sealassembly which is commonly referred to as an inside seal and isassociated with an apparatus which includes a wall 11 having an opening12 through which extends a rotatable shaft 13. The seal assembly 10includes a housing 14 secured to the wall 11 by conventional means, suchas bolts (not shown).

The housing 14 has a stationary seal means 16 associated therewithwhich, as illustrated in FIGS. 1 and 2, includes a stationary annularseal member 17 positioned in surrounding relationship to the shaft 13and nonrotatably supported by a stationary annular member 18. Theannular member 18, commonly referred to as a gland, is fixedly connectedto the housing 14 by any conventional means, such as by the use ofthreaded studs 21 and nuts 22. The annular seal member 17,

commonly referred to as a gland insert, is nonrotatably connected to thegland 18 by means of one or more locking pins 19 which are fixedlysecured to the gland insert 17 and extend radially into slots formed inthe gland 18. Suitable sealing means 23 and 24, such as gaskets, areprovided between the gland insert 17 and the gland 18 and the housing14.

The gland insert 17 has an axially projecting flange 26 on the inner endthereof which forms an annular recess in the inner end of the insert. Anannular face ring 27 is disposed within the recess formed in the glandinsert 17, with the face ring 27 beingclosely surrounded by the flange26. The face ring 27 is nonrotatably con nected to the gland insert 17,such as by the creation of an interference fit between the flange 26 andthe face ring 27. The face ring 27, which in a preferred embodiment isconstructed of tungsten carbide, has an accurately finished radial sealsurface 28 formed on the inner axial end thereof. The gland insert 17and face ring 27 are suitably radially spaced from the rotatable shaft13 to define an annular clearance space 29 therebetween to permitangular or lateral movement or deflection of the shaft relative to thewall 11.

The stationary seal means 16 is disposed for sealing coaction with arotatable seal means 31 encircling and rotatable with the shaft 13. Therotatable seal means 31 includes an annular collar assembly 32 fixedlysecured to the shaft 13. The collar assembly 32 is of a two-piececonstruction and includes first and second ringlike collar members 33and 34 encircling the shaft and axially fixedly connected by anysuitable means, such as a plurality of screws 36. The first and secondringlike collar members 33 and 34 have substantially radial end faces 37and 38, respectively, formed thereon and abuttingly engaged when thecollar members are clampingly held together by the screws 36. The firstcollar member 33 is also provided with a radially movable set screw 39which, in a conventional manner, is adapted to be clampingly engagedwith the periphery of the shaft 13 for axially and nonrotatably securingthe collar assembly 32 to the shaft 13.

The rotatable seal means 31 also includes a rotatable annular sealmember 41 positioned in surrounding relationship to the shaft 13. Therotatable seal member 41 has a cuplike configuration and includes anannular flange 42 extending axially toward the gland insert 17. Theflange 42 forms an annular recess in the outer axial end of the sealring 41. A face ring 43 is axially seated within the recess formed inthe rotatable seal member 41 and is nonrotatably connected to the sealmember 41, such as by the creation of an interference fit between theflange 42 and the face ring 43. The face ring 43 is provided with anaccurately finished radial seal surface 44 on the axial end thereof,which seal surface 44 is urged against the seal surface 28 to form arotatable'sliding seal therebetween. The seal. ring 43, like the sealring 27, is also preferably constructed from tungsten carbide.

The annular seal member 41 is nonrotatably and sealingly connected tothe collar assembly 32 by means of an intermediate bellows seal 47. Thebellows seal 47, as illustrated in FIGS. 1 and 2, encircles the shaft 13and extends axially between the second collar member 34 and the rotatingseal member 41. One end of the bellows 47 is fixedly and sealinglyconnected, as by welding, to the collar member 34, whereas the other endof the bellows 47 is fixedly and sealingly connected to the annular sealmember 41, such as by welding. The bellows seal 47 is of substantiallyconventional construction and includes a plurality of individual bellowsplates, preferably constructed from stainless steel, with the adjacentbellows plates alternately having their inner and outer peripherieswelded together around the complete peripheries thereof to provide afluid-tight joint while at the same time permitting the bellows to havethe desired flexibility. Such bellows are well known, and thus furtherdescription of same is not believed necessary.

The rotatable seal means 31 is also provided with resilient means forurging the annular seal member 41 toward the gland insert 17 to thusmaintain the seal faces 28 and 44 in sealing engagement with oneanother. The resiliency of the bellow may be sufficient for thispurpose. However, the seal assembly may, if necessary, be provided witha conventional coil spring (not shown) encircling the shaft 13 andpositioned, as is conventional, with the opposite ends thereof inengagement with the collar assembly 32 and the annular seal member 41.Such a coil spring is normally maintained under compression tocontinuously resiliently urge the face ring 43 into engagement with facering 27. Also, the spring can, if desired, be positioned in the interiorof the bellows to prevent the spring from being contacted by the fluidcontained within the chamber 48.

To prevent the fluid within chamber 48 from gaining access into theinterior of the bellows 47, the collar assembly 32 is provided withpacking means 49 associated therewith and disposed for creating asealing engagement with the periphery of the shaft 13. The packing means49 of the present invention includes an annular recess 51 formed in thecollar member 34, which recess 51 extends axially inwardly from thetransverse end face 38 and is disposed to directly surround theperiphery of the shaft 13. The bottom of the recess 51 is defined by asubstantially radial base wall 52 which lies within a planesubstantially perpendicular to the longitudinally extending axis of theshaft 13. The recess 51 also has a sidewall 53 which slopes inwardlytoward the shaft periphery as it extends axially away from the endsurface 38. The tapered sidewall 53 thus comprises a truncated conicalsurface. The other axial end of the recess 52 is substantially closed bythe radial end face 37 of the collar member 33 when the collar members33 and 34 are clampingly and axially connected by the screws 36. The endface 37, which is substantially parallel to the base wall 52, thuscoacts with the base wall 52 and the tapered sidewall 53 to form asubstantially closed annular recess disposed in communication with andin surrounding relationship to the shaft 13.

The packing means 49 also includes an annular pack ing ring 54 which isdesigned to totally occupy the recess 51. The packing ring 54, in thepreferred embodiment of the invention, is constructed of a multilayer,laminated construction and is preferably formed from a plurality of thinwasher-like plates 56 of graphite. The

.plates 56, in the illustrated embodiment, are axially plates 56. As astill further alternative, the packing ring 54 can be formed from acontinuous flat member wound radially to form a concentric spiralmember, with the axial width of the individual coils of the spiralmember corresponding to the axial length of the packing ring. Theselater-mentioned constructions are disclosed in greater detail in mycopending application Ser. No. 837,061.

The packing ring 54 is initially positioned within the recess 51 betweenthe opposed axial support surfaces 37 and 52. Thus, when the collars 33and 34 are axially moved together, as by tightening of the screws 36,the packing ring 54 is axially compressed between the surfaces 37 and52, which axial compression is sufficient to permit the surfaces 37 and38 to be disposed in abut ting engagement with one another. As thepacking ring 54 is being axially compressed due to movement of surface37 toward the back support surface 52, the tapered sidewall 53 exerts awedging action on the pack-' ing ring 54 causing same to be radiallycompressed inwardly so that it is tightly compressed against andsealingly engages the external peripheral surface of the shaft 13. Sinceshaft 13 is of substantially uniform diameter in the region of thecollar assembly 32, the packing ring 54 effects a radially directedsealing engagement with the shaft periphery.

In a preferred embodiment of the invention, the tapered peripheralsurface 53 extends at an angle relative to the axial direction of theshaft 13 which lies within the range of 5 and 25, and preferably isapproximately 15. Also, while the rear surface 52 has been disclosed asbeing substantially radial with respect to the shaft axis, neverthelessthis surface can deviate slightly from this desired transverserelationship, so long as this angular deviation is realtively small andpreferably does not exceed approximately 10. However, forming the rearsupport surface 52 radially with respect to the shaft axis is preferred.

The packing ring 54, as explained above, is of a graphite material andpreferably of a multilayer or laminated graphite material sold under thename Grafoil (trademark). It has been experimentally discovered that asuccessful seal can be achieved if the graphite has an initial densityof between 35 and pounds per cubic foot. After the graphite packing ringhas been installed within the collar assembly and pressed between thesurfaces 37 and 52, the packing ring undergoes limited compression sothat the actual density of the packing ring 54 when installed isapproximately between 40 and pounds per cubic foot. While graphitematerial deviating from these density ranges can obviously be used ifspecial attention is paid to the magnitude of compression, neverthelessthe above ranges represent the densities which have been discovered toprovide the most efficient and most durable sealing relationship.

For further explanation and discription of the graphite material and itsphysical properties, and of the manner in which it coacts with the wedgesurface, reference is made to my copending application Ser. No. 837,061.

OPERATION The operation of the mechanical seal construction of thepresent invention will be briefly described to insure a completeunderstanding thereof.

During operation of the seal assembly 10, the shaft 13 will be rotatedrelative to the wall 11 and a pressurized fluid will be contained withinthe chamber 48. To prevent the pressurized fluid from escaping from thechamber 48, a seal is provided by the sliding contact between therelatively rotating seal surfaces 28 and 44, which surfaces aremaintained in snug sliding contact with one another due to the resilienturging of the bellows 47. Further, since the rotating seal member 41 isnot fixedly mounted on the shaft but is slightly radially spacedtherefrom, the seal member 41 and the seal ring 43 mounted thereon willfreely float relative to the shaft so that the seal surface 44 willalways be maintained in proper seating and sealing engagement with theseal surface 28.

Due to the clearnace and relative movement of seal member 41 relative tothe shaft, there is additionally provided the bellows 47 sealinglyconnected between the collar member 34 and the seal member 41 forpreventing the pressurized fluid within chamber 48 from escaping betweenthe shaft and the seal member 41. Also, to prevent the pressurized fluidin chamber 48 from escaping along the surface of the shaft between theshaft and the collar assembly 32, same is additionally provided with thepacking means 49 associated therewith, which packing means sealinglyengages the periphery of the shaft 13 and prevents fluid from escapingtherealong. The packing means 49, in conjunction with the bellows 47,thus effectively prevents fluid within chamber 48 from escaping alongthe surface of the shaft.

While the seal assembly illustrated and described utilizes coacting sealmembers having transverse seal surfaces disposed in relatively rotatableand sliding engagement with one another, it will be recognized that thebellow seal construction of the present invention, particularlyincorporating therein the bellows seal 46 and the packing means 49, canalso be utilized for sealingly connecting two relatively movable butnonrotatable members, in which case the provision of the relativelyrotatable sliding seal faces would not be necessary.

It will also be recognized that the collar assembly 32 can be modifiedso that the collar members 33 and 34 are resiliently urged, as bysprings, into engagement with one another to axially and radiallycompress the packing ring 54 therebetween to cause same to sealinglyengage the periphery of the shaft in substantially the same manner asdisclosed in my abovementioned copending application Ser. No. 837,061.For example, in this proposed modification, the collar member 34 can befixedly secured to the shaft, as by means of a set screw, and the collarmember 33 can be resiliently urged, as by springs, toward the collarmember 34. The collar member 33 can have a suitable projection thereonadapted to extend into the leftward end of the recess 51 for causing thepacking ring 54 to be axially and radially compressed between the collarmembers and the shaft periphery.

While the rotating seal member 41 has been disclosed as supported by thebellows 47, with the bellows holding the seal member 41 substantiallynonrotatable relative to the shaft 13, it will be appreciated that otherstructure, such as a pin-and-slot connection, could be provided betweenthe member 41 and the shaft 13 to nonrotatably connect same.

Although a particular preferred embodiment of the invention has beendisclosed in detail for illustrative purposes, it will be recognizedthat variations or modifications of the disclosed apparatus, includingthe rearrangement of parts, lie within the scope of the presentinvention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a mechanical seal construction, which can be utilized underconditions of extremely high or extremely low temperatures, particularlyabove 600 F. and below l00 F., and designed for use between a wall and ashaft extending therethrough and rotatable relative thereto, saidmechanical seal construction having a pair of seal elements havingmutually contacting sealing faces, one seal element being fixed withrespect to said wall and the other seal element being capable ofrotation in response to rotation of said shaft, the improvementcomprising:

annular collar means surrounding and fixedly secured to said shaft, saidcollar means including an annular recess disposed directly adjacent andin surrounding relationship to said shaft; elongated flexible bellowsmeans extending between and sealingly connected to said other sealelement and said collar means for supporting said other seal element andpermitting same to move relative to said collar means, said bellowsmeans including a plurality of metal plates alternately having theirinner and outer peripheries sealingly connected;

sealing means coacting between said collar means and said shaft forcreating a sealed relationship therebetween, said sealing meansincluding an annular ringlike sealing member constructed of multilayergraphite material and disposed within said annular recess; and

said collar means including means for causing both axial and radialcompression of said graphite sealing member, said last-mentioned meansincluding a substantially conical wall disposed in surroundingrelationship to and partially defining said annular recess, said conicalwall being slightly tapered relative to the axis of said shaft forcausing said sealing member to be radially compressed into sealingengagement with the periphery of said shaft.

2. A seal construction according to claim 1, wherein said collar meansincludes first and second ringlike collar members surrounding andfixedly secured to said shaft, said first and second collar membersrespectively having first and second surfaces formed thereon, said firstand second surfaces being substantially opposite one another andsubstantially perpendicular to the iongitudinally extending axis of saidshaft;

said collar means also including means for nonrotatably interconnectingsaid first and second collar members while permitting said first andsecond collar members to be moved axially toward one another so thatsaid first and second surfaces are axially moved toward one another;

said annular recess extending outwardly from the inner peripheralsurface of said first collar member and extending axially from saidfirst surface part way through said first collar member, said firstcollar member having an annular support wall defining one end of saidrecess, said annular support wall being substantially perpendicular tothe longitudinal axis of said shaft; and

said annular sealing member being disposed within said annular recessand axially compressed between said support wall and said secondsurface. 3. A seal construction according to claim 2, wherein said aconical wall extends between said first surface and said support wallfor defining the outer periphery of said annular recess, said conicalwall tapering inwardly toward the axis of said shaft as it extends fromsaid first surface axially toward said support wall, whereby saidannular sealing member is simultaneously axially and radially compressedas said first and second collar members are axially moved toward oneanother. 4. A seal construction according to claim 3, wherein saidmultilayer sealing member is of laminated construction and includes aplurality of thin washerlike plates of graphite having a thickness ofapproximately 0.005 to 0.010 inch.

5. A seal construction according to claim 3, wherein said first collarmember has a further surface disposed on the side thereof opposite saidfirst surface, and said bellows means having one end thereof fixedly andsealingly connected to said first collar member adjacent said furthersurface.

6. A seal construction according to claim 3, wherein said conical wallextends at an angle of approximately 15 relative to the axis of saidshaft.

7. A seal construction according to claim 1, wherein said conical wallextends at an angle of approximately 15 relative to the axis of saidshaft.

8. A seal construction according to claim 1, wherein said collar meansincludes a pair of opposed and substantially parallel walls defining theopposite sides of said recess, said walls being substantiallyperpendicular to the axis of said shaft, and said conical wall extendingbetween said pair of side walls and defining the bottom of said recess,said conical wall extending at an angle of between approximately 5 and25 relative to the axis of said shaft.

1. In a mechanical seal construction, which can be utilized underconditions of extremely high or extremely low temperatures, particularlyabove 600* F. and below -100* F., and designed for use between a walland a shaft extending therethrough and rotatable relative thereto, saidmechanical seal construction having a pair of seal elements havingmutually contacting sealing faces, one seal element being fixed withrespect to said wall and the other seal element being capable ofrotation in response to rotation of said shaft, the improvementcomprising: annular collar means surrounding and fixedly secured to saidshaft, said collar means including an annular recess disposed directlyadjacent and in surrounding relationship to said shaft; elongatedflexible bellows means extending between and sealingly connected to saidother seal element and said collar means for supporting said other sealelement and permitting same to move relative to said collar means, saidbellows means including a plurality of metal plates alternately havingtheir inner and outer peripheries sealingly connected; sealing meanscoacting between said collar means and said shaft for creating a sealedrelationship therebetween, said sealing means including an annularringlike sealing member constructed of multilayer graphite material anddisposed within said annular recess; and said collar means includingmeans for causing both axial and radial compression of said graphitesealing member, said lastmentioned means including a substantiallyconical wall disposed in surrounding relationship to and partiallydefining said annular recess, said conical wall being slightly taperedrelative to the axis of said shaft for causing said sealing member to beradially compressed into sealing engagement with the periphery of saidshaft.
 2. A seal construction according to claim 1, wherein said collarmeans includes first and second ringlike collar members surrounding andfixedly secured to said shaft, said first and second collar membersrespectively having first and second surfaces formed thereon, said firstand second surfaces being substantially opposite one another andsubstantially perpendiculaR to the longitudinally extending axis of saidshaft; said collar means also including means for nonrotatablyinterconnecting said first and second collar members while permittingsaid first and second collar members to be moved axially toward oneanother so that said first and second surfaces are axially moved towardone another; said annular recess extending outwardly from the innerperipheral surface of said first collar member and extending axiallyfrom said first surface part way through said first collar member, saidfirst collar member having an annular support wall defining one end ofsaid recess, said annular support wall being substantially perpendicularto the longitudinal axis of said shaft; and said annular sealing memberbeing disposed within said annular recess and axially compressed betweensaid support wall and said second surface.
 3. A seal constructionaccording to claim 2, wherein said a conical wall extends between saidfirst surface and said support wall for defining the outer periphery ofsaid annular recess, said conical wall tapering inwardly toward the axisof said shaft as it extends from said first surface axially toward saidsupport wall, whereby said annular sealing member is simultaneouslyaxially and radially compressed as said first and second collar membersare axially moved toward one another.
 4. A seal construction accordingto claim 3, wherein said multilayer sealing member is of laminatedconstruction and includes a plurality of thin washerlike plates ofgraphite having a thickness of approximately 0.005 to 0.010 inch.
 5. Aseal construction according to claim 3, wherein said first collar memberhas a further surface disposed on the side thereof opposite said firstsurface, and said bellows means having one end thereof fixedly andsealingly connected to said first collar member adjacent said furthersurface.
 6. A seal construction according to claim 3, wherein saidconical wall extends at an angle of approximately 15* relative to theaxis of said shaft.
 7. A seal construction according to claim 1, whereinsaid conical wall extends at an angle of approximately 15* relative tothe axis of said shaft.
 8. A seal construction according to claim 1,wherein said collar means includes a pair of opposed and substantiallyparallel walls defining the opposite sides of said recess, said wallsbeing substantially perpendicular to the axis of said shaft, and saidconical wall extending between said pair of side walls and defining thebottom of said recess, said conical wall extending at an angle ofbetween approximately 5* and 25* relative to the axis of said shaft.